Hollow metal article and method and apparatus for forming same



G. C. BURD HOLLOW METAL ARTICLE AND METHOD AND APPARATUS FOR FORMING SAME March 28, 1961 3 Sheets-Sheet 1 Filed March 12, 1956 INVENTOR GORMAN 6. EURO G. C. BURD HOLLOW METAL ARTICLE AND METHOD AND APPARATUS FOR FORMING SAME March 28, 1961 3 Sheets-Sheet 2 Filed March 12, 1956 0 M we we V mN A W o 6 BY W ATTORNEY March 28, 1961 IURD 2,976,549

G. C. HOLLOW METAL ARTICLE AND METHOD AND APPARATUS FOR FORMING SAME Filed March 12, 1956 3 Sheets-Sheet 3 no 7 I49 INVENTOR GORMAN C. BURD BY I WA'ILTORNEY ited Sr HOLLOW METAL ARTICLE AND METHOD AND APPARATUS FOR FORMING SAME Filed Mar. 12, 11 56, Ser. No. 570,956

8 Claims. (Cl. Ili -153) This invention relates to internally threaded or spirally ridged metal articles of hollow configuration, such as bushings, ferrules, connectors and similar items, and to a method and apparatus for forming an internal thread or raised spiral ridge upon the interior of a metal article by successive impacts or swaging.

Heretofore, it has been commercial practice to form brass ferrules or connectors and especially those forming components of hose fittings and the like with internal threads by conventional tapping operations. Such operations are expensive and time consuming and result in substantial waste of metal.

The present invention provides a tubular member or ferrule having an internal thread or spiral ridge formed by subjecting the exterior surface of the member or ferrule to rapid successive impacts forcing the metal of the ferrule or connector inwardly into a spiral recess formed on a suitable matrix or support to establish an internal thread or spiral ridge of reciprocal shape on the interior surface of the member or ferrule.

The invention embraces the provision of a method of engaging the exterior cylindrical surface of a hollow article by dies reciprocating at frequencies of several thousand impacts per minute whereby the metal of the article is cold flowed or pressed inwardly under the successive blows or impacts of the reciprocating dies into engagement with a configurated matrix whereby the interior surface of the article acquires the reciprocal configuration of the matrix.

Another object of the invention resides in a method of concomitantly rotating and reciprocating dies into engagement with the exterior region or surface area of a ferrule or hollow metal article to force the metal inwardly into a grooved matrix and wherein the matrix and ferrule or metal article are resiliently supported for limited rotation about the axis of the matrix to provide for a slight oscillatory movement of the matrix and ferrule or hollow article during effective operation of the dies.

Another object of the invention is is the provision of a method of swaging the metal of tubular material inwardly about a threaded or spiral formation to impress an internal thread or spiral ridge on the interior wall of the material wherein the steps or operations of the method are carried on automatically and in proper sequential relation.

Another object of the invention resides in the provision of apparatus for impacting or swaging a thread or spiral ridge on the interior surface of a hollow metal blank or ferrule and at the completion of the thread or ridge forming operations the finished workpiece is automatically rotated to discharge the workpiece from a support or matrix.

Another object of the invention resides in the provision of apparatus for swaging a configuration on the interior surface of a hollow metal article wherein the articles are fed to a loading station and automatically conveyed to the configuration forming station and automatically 2,9754% Patented Mar. 28, 1961 withdrawn from said station at the completion of the configuration forming operation and discharged from a support.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which maybe preferred, in which:

Figure 1 is a side elevational view showing a form of apparatus for carrying out the method of the invention;

Figure 2 is a top plan view of the apparatus shown in Figure 1;

Figure 3 is an end view illustrating the swaging die arrangement;

Figure 4 is an enlarged fragmentary detail view of a portion of the arrangement illustrated in Figure 3;

Fgure 5 is an elevational view illustrating a matrix for the ferrule or hollow metal article and mounting means therefor;

Figure 6 is a vertical sectional view through a completed ferrule showing the spiral ridge or thread formed on the interior thereof;

Figure 7 is an end view of the ferrule shown in Figure 6;

Figure 8 is a vertical sectional view taken substantially on the line 8-8 of Figure 2;

Figure 9 is an end view of the arrangement shown in Figure 8;

Figure 10 illustrates a modified form of resilient support and mounting means for the matrix or arbor;

Figure 11 illustrates another form of yieldable or resilient mounting means for the matrix, and

Figure 12 illustrates a form of mechanically operated means for reciprocating the matrix or work support and components associated therewith.

While the forms of apparatus of the invention illustrated in the drawings are especially adaptable for carrying out the method of forming internal threads or spiral ridges on ferrules, bushings or other tubular or hollow metal articles, it is to be understood that the apparatus and method of the invention may be used for forming other shapes or configurations on the interiors of hollow articles or Work pieces or wherever the invention may be found to have utility.

The apparatus and method of the invention has particular utility in forming a spiral thread or ridge on.

the interior of a ferrule of the character shown in Figures 6 and 7, this type of ferrule being especially usable in securing a coupling construction to flexible rubber or plastic hose.

Referring to the drawings in detail and more especially to Figures 1 and 2, there is illustrated a form of apparatus of the invention for swaging or impacting the metal of a tubular or hollow element to form a spiral ridge or thread on the interior surface thereof. The apparatus illustrated includes a rotary swaging means carried by a frame 10 having an elongated extension 11 and a swaging or head portion 12.

The swaging component or mechanism of the apparatus is inclusive of a shaft 16 journalled in suitable bearings (not shown) carried by the head portion 12, the shaft being equipped with a driving pulley or sheave 18 driven by a plurality of driving belts 20 from a suitable motor (not shown).

Formed upon an opposite end zone of the shaft 16 is an enlarged portion 22 provided with a diametrically arranged slot defined by parallel walls 24. Slidably disposed in the slot in the portion 22 are matched or mating dies 26 and impacting or swaging hammers or members 23. Surrounding the portion 22 is a freely rotatable annular cage 39. The annular cage 36 is formed with circumferentially spaced cylindrical chambers, each of which receives and accommodates a cylindrically shaped abutment element or swaging roll 34. v

As particularly shown in Figure 4, the outermost surface zones of the hammers 28 are convexly curved as at 36 and are normally disposed in the position shown in Figure 4. In this position the dies 26 are separated by a space indicated at 38. The impacting elements or hammers 28 extend outwardly so that during rotation of the shaft 16 and portion 22 thereof carrying the dies, the hammers or swaging members 28 are moved inwardly as the hammers roll along a path successively engaging the peripheries of the cylinders or rolls 34. As soon as the hammers 28 move past a pair of rolls or cylinders 34 the hammers and dies 26 are moved outwardly by centrifugal forces of rotation as the hammers 28 move into zones between adjacent rolls 34 as shown in Figure 4, as each pair of diametrically disposed rolls or cylinders 34- are engaged by the rotating hammers 28, the latter are moved inwardly again to close the mating dies 26.

The shaft 16 and enlarged portion 22 and the dies and hammers carried thereby are rotated at a speed relative to the number of cylinders or rolls 34 so that upwards of five thousand or more impacts or reciprocations per minute are imparted to the mating dies 26 whereby a workpiece inserted between the mating dies receives swaging impacts at high frequencies. The reciprocating action of the dies and hammers is continuous during rotation of the shaft 16 irrespective of the presence of a workpiece between the dies.

A finished ferrule or tubular article 42 is shown in Figures 6 and 7 and comprises an annular wall portion 44, an inwardly extending flange 45 adjacent one end and a spiral ridge or thread 46 formed on the interior wall thereof.

The unthreaded ferrule, work piece or tubular member 42 shown in Figure is adapted to be carried upon an arbor, matrix or support 50 during the thread or configuration forming operations. As shown in Figure 5, the arbor, matrix or support 50 is formed with a spiral recess or groove 52 into which the metal of the workpiece or ferrule blank 42 is cold flowed or forced under the swaging impacts imparted to the dies 26.

As shown in Figures 1, 2, 5 and 8, the arbor or work support 50 is resiliently mounted upon or supported by a resilient or yieldable means or spring 54 which, in the embodiment illustrated, is in the form of a coil spring. By reason of the resilient supporting means for the arbor 50, the latter may be referred to as a floating support or arbor which is capable of limited rotary and longitudinal movement permitted by the spring 54 for purposes to be hereinafter explained.

The arbor or support 50 is formed with a tenon 56 about which an end zone of the coil spring 54 is tightly wound, the tension in the spring serving to grip the tenon 56 to establish a connection between the arbor 50 and the spring 54.

The support 50, the workpiece carried thereby and the coil spring 54 are adapted to be reciprocated by suitable means. In the embodiment illustrated in Figures 1 and 2 a fluid actuator or fluid servo-motor 60 is provided for the purpose. Mounted upon the bed frame 11 of the apparatus is an upwardly extending member 62 which supports an elongated cylinder 64 in which is slidably disposed a piston 65. The piston 65 is mounted upon a piston rod 66, the latter projecting through a stufiing or sealing gland 68, the piston rod 66 being provided at one end zone with a threaded portion 70. Threaded upon the portion 70 of the piston rod 66 is a. laterally or trans versely extending finger or bracket 72 which may be locked in adjusted position on the piston rod 66 by means of a locking nut 73. a

The portion of the piston rod 66 projecting from the cylinder 64 is formed with a tenon 74 adapted to extend into and be gripped by the end zone of spring 54 opposite the end carrying the arbor or support 50 as shown in Figure 5. The actuator or servo-motor 60 illustrated is of the type actuated by compressed air but may be of a type actuated by liquid under pressure such as oil. The actuator 60 is of the two-way type, that is, fluid pressure is effective to cause successive reciprocations of the piston 65, piston rod 66 and the components connected thereto.

The actuator 60 is provided with suitable valve means (not shown) for admitting fluid alternately into opposite ends of the cylinder 64. The valve means may be of the solenoid operated type and mounted upon the member 62 are housings 76 and 77 which respectively enclose switch means for initiating the operation of the solenoid actuated valves controlling the flow of fluid into and away from the cylinder 64.

Secured to the transversely extending bracket 72 carried by the piston rod 66 is a rod or bar 80 which is slidably disposed in openings or passages formed in the switch housings 76 and 77. Adjustably supported upon the bar or rod 80 are abutments or switch actuating blocks 82 and 83. The abutment or block 83 is adapted to engage a switch plunger 85 which closes a switch within the housing 77 for actuating a solenoid valve (not shown) to direct fluid under pressure into the righthand end of the cylinder 64 as viewed in Figure 2.

This action moves the piston rod 66 and components carried thereby in a lefthand direction as viewed in Figure 2. The abutment or block 82 carried by the rod 80 is adapted to engage a switch plunger 87 when the piston 65 and piston rod 66 reach their limits of movement in a lefthand direction as viewed in Figure 2.

When the abutment 82 engages the switch plunger 87, the switch means contained in the housing 76 actnates a soleniod controlled valve (not shown) to admit fluid under pressure into the opposite end zone of the cylinder 64 at the lefthand side of the piston 65 causing the piston 65, piston rod 66 and parts carried thereby, to move in a righthand direction reaching the position shown in Figures 1 and 2. The valves also provide for alternately venting or relieving the pressure on opposite sides of the piston in effecting reciprocation thereof.

Mounted upon the frame bed 11 of the machine is a bracket or member 90. As shown in Figure 8, the member 90 is formed with a bore axially aligned with the longitudinal axis of movement of the work support 50 and the spring 54, the bore being provided with a bushing 92 which slidably accommodates the spring 54.

The work pieces or ferrule blanks 42 are adapted to be contained within a chute or magazine 94 secured to or carried by the head structure 12 of the apparatus as shown in Figures 1 and 2. The shaft 16, carrying the swaging or impacting dies 26, is provided with an axial bore 96 in which is slidably supported a plunger 98, the latter being biased to its outermost position, as shown in Figure 1, under the influence of an expansive coil spring 99 contained within the bore 96.

When the arbor 50 is advanced to engage the lowermost ferrule blank 42' in the magazine 94 and convey the ferrule blank into the swaging dies, the plunger 93 engages the flange portion 45 of the ferrule workpiece to prevent dislodgement of the workpiece from the threaded arbor 50.

- The member 90 supports a means for removing or unthreading the completed ferrule or tubular member 42 from the arbor or support 50 after the thread-forming operation has been completed. As shown in Figures 1, 2 and 8, the member 90 is provided with bearings 101 disposed at either side of the guide bushing 92. Jounralled in the bearings 101 are shafts 102, each shaft being provided with a pulley 104.

A motor 1% supported by the bed frame 11 of the machine is provided with a drive pulley 107 and a driving belt 168 engages pulleys 194 and the drive pulley '107 whereby the shafts 102 are simultaneously driven by the motor 106. Each of the shafts 102 is provided with a roll 110 which is preferably formed with a tapered or frusto-conically shaped portion 111 which may be serrated or'roughened to establish an effective gripping engagement with the extremity of a completed ferrule 42 carried by the support or arbor 50.

The rolls 116 are rotated in a direction whereby engagement of the tapered surfaces 111 with the extremity of the ferrule 42 effectively remove the completed ferrule from the arbor by rotating the ferrule in a direction to unthread or dethread the same from the arbor.

In order to maintain the proper positioning of the work piece or ferrule blank 4-2 in the swaging dies, it-has been found that the spiral recess or thread formed on the arbor 50 should be opposite to the direction of spiral of the supporting spring 54. Thus if a righthand thread or spiral recess is formed on the work arbor 50, the coil spring 54 is formed with a lefthand spiral formation.

During the thread forming operations, the hammers 2S successively engaging the rolls 34 establish successive impacting contacts of the dies 26 with the exterior surface of the ferrule blank, and during each contact the ferrule blank is slightly rotated in the direction of rotation of the swaging or impacting dies. This rotation reacts on the spring 54 causing the latter to be slightly wound more tightly to exert additional pressure acting on the ferrule and the support.

The reaction of each impacting or swaging blow in slightly rotating the spring 54', unbalances the spring, setting up a torque or accumulated energy therein which is effective, in the periods between successive impacts, to rotate or return the workpiece to its initial position to receive the next impact of the dies. In this manner the workpiece and arbor are rapidly oscillated during the swaging operations to attain uniform swaging throughout the periphery of the workpiece.

A spring or resilient means 114 is preferably disposed between the bracket or finger 72 carried by the piston rod 66 and a wall of the switch housing 76 as shown in Figure 2 for the purpose of slowing up or retarding retractive movement of the piston rod 66 as it approaches the end of its retractive stroke in order to enable the rotating rolls 110 to dethread or remove the completed ferrule from the support 50.

The operation of the apparatus of the invention above described in carrying out the method is as follows:

A supply of tubular workpieces or unthreaded ferrules 42 is maintained in the chute 94. The chute 94 may be provided with an extension (not shown) to contain an ample number of workpieces or blanks. The motor driving the shaft 16 is energized and the motor 1% driving the work removing rolls 11th is also energized. The arbor or support 50, the spring 54, and the piston and piston rod 66 of the fluid actuator 60 are in retracted position as shown in Figures 1 and 2.

Pressure fluid such as compressed air is supplied to the fluid actuator 60 by manipulating a control valve 118 in the compressed air supply line 120. As the switch operating abutment or block 83 has engaged the switch plunger 85 at the end of the stroke of the piston rod 66, the solenoid valve operated by the switch contained in the housing 77 admits compressed air or pressure fluid into the righthand end of cylinder 64 as viewed in 'Figures l and 2 to exert pressure upon the piston 65 to advance the piston, the piston rod 65, spring 54 and arbor or support 50 in a lefthand direction.

The spirally recessed or threaded arbor 50 moves through an opening in the wall of the chute 9 and telescopes with and engages the interior zone of a ferrule blank or workpiece 42, the engaged blank being the lowermost one in the chute in alignment with the work 6 support 5%. The ferrule blank 42 fitting over the work support 59 is conveyed to the work performing station, that is, to a position wherein the ferrule blank is disposed within the space between the dies 26.

During the advancing movement of the ferrule blank and work support 56, the plunger 98 holds the ferrule blank in proper position on the arbor or support and maintains the blank in this position during the work performing or swaging operations under the expansive pressure of the spring 99 contained in the bore 96 in the shaft 16.

Assuming that a righthand spiral ridge or thread is to be formed on the interior of the ferrule blank 42 carried by the support, the shaft 16 is rotated in the same direction, that is, as viewed in Figure 3 the shaft 16 carrying the dies 26 is rotated in a counter-clockwise direction. The shaft 16, being rotated continuously, establishes a continuous high frequency reciprocation of the impacting or swaging dies 26, the entrance zone 27 of the dies being tapered in order to facilitate entrance of the ferrule blank into engagement with the dies,

During rotation of the shaft 16, the hammer members 28 are moved into and out of engagement with the cylindrical members 34, an even number of cylindrical members 34 being employed so that both hammers 28 are simultaneuosly' moved inwardly against the dies 26 at each period of engagement of the curved surface 36 of each hammer with one of the cylindrical members 34. This action will be apparent from examination of Figure 4.

The shaft 16 is rotated at a speed to establish upwards of five thousand or more reciprocations and impacts per minute of the hammers 23 against the dies 26 whereby the latter are moved into swaging or impacting engagement against the exterior peripheral zone of the ferrule blank, forcing the metal of the blank with each impact inwardly so that the metal of the ferrule wall is gradually moved or cold flowed into the spiral groove formed on the arbor or support 50 to form a reciprocally shaped spiral ridge or thread on the interior of the blank.

It should be noted that the cage 39 supporting the cylindrical members 34 is freely rotatable in the race or chamber containing the assembly of cage and cylindrical I members. Thus as the curved surfaces 36 of each of the hammers 28 rides over a cylindrical member 34, the cage 30 and cylindrical members move or rotate a slight distance in the same direction of rotation as the shaft During this slight rotation of the cage Bil, with each inward impact of the hammers 28 and dies 26, the latter are in engagement with the exterior zone of the ferrule bank for a short period of time so that the blank 42, and the arbor 50 supporting the same are rotated a slight amount in the direction of rotation of the shaft 16. During this slight rotation of the ferrule blank, the spring 54 is stressed and distorted in accomodating this slight rotation of the ferrule,

However, as soon as the surfaces 36 of the hammers 28 move away from a pair of the cylindrical members 34, centrifugal forces move the hammers 28 and dies 26 outwardly, the latter releasing their grip upon the ferrule for a short period of time. During the period of release of the dies 26 from engagement with the ferrule blank 42', the energy stored in the spring 54, by reason of its unbalanced condition due to the rotation of the ferrule and arbor in a counter-clockwise direction Viewed from the right hand of Figure 1, causes a return rotation of the ferrule blank and arbor 50 toward their normal position.

The dies 26 are again moved into engagement with th ferrule by the hammers 28 engaging the next succeeding pair of cylindrical members 34. Thus, during the work performing operations of swaging or impacting the metal of the ferrule blank into the spiral groove on the arbor 50, the ferrule and arbor 5% are repeatedly oscillated through the above described action, the frequency of oscillations of the ferrule and arbor being equal to the number of impacts of the dies 26 against the exterior surface of the ferrule blank.

Due to the resiliency of the supporting spring 54 whereby the arbor t) and ferrule blank 42' virtually float within the working zone of the dies 26, there is no relative movement occurring between the threaded arbor 5'0 and the ferrule blank, so that a perfect impression of the spiral configuration on the arbor 50 is formed on the interior wall of the ferrule blank.

The swaging or metal impacting operations or movements of the dies 26 are carried on continuously so that the ferrule blank is subjected to swaging operations as it enters the dies by the advancing movement of the piston rod 66 under the influence of fluid under pressure introduced into the righthand end of the cylinder 64. When the ferrule is completely within the working zone of the dies 26, the abutment 82 on the rod 30 has reached a position engaging the switch plunger 87, actuating the switch to operate a solenoid valve to admit compressed air into the lefthand end of cylinder 64 as viewed in Figures '1 and 2 to exert pressure in a righthand direction against the piston 65.

Movement of the piston rod 66 in a righthand direction moves the spring 54, the arbor 5t), and the ferrule 42 with an internal thread or spiral ridge formed thereon in a righthand direction, withdrawing the ferrule from engagement with the dies 26. The completed ferrule on the arbor 50 is withdrawn through the opening in the wall of the chute 94, permitting the blanks in the chute to advance whereby the next succeeding ferrule blank moves downwardly into a position in alignment with the support or arbor 50.

Continued retractive movement of the arbor 50 and spring 54 brings the edge wall or zone of the completed ferrule 42 into engagement with the rotating rolls 1141. The end wall of the ferrule is engaged by the serrated tapered portions 111 of the rapidly rotating rolls, and as the rolls are rotating in a direction to unthread or dethread the completed ferrule from the arbor, the ferrule is thus quickly removed from the arbor or matrix 50.

While fluid pressure, acting in the lefthand end of the cylinder 64, continues to urge the piston 65 into a righthand direction during the period that the ferrule'is in engagement with the rolls 110, the spring 114 retards retraction of the arbor during removal of ferrule therefrom. The retarded movement of the arbor is pemitted by extension of the spiral spring 54. When the completed ferrule is removed from the arbor 50, it falls by gravity into an inclined chute or receiving zone (not shown) and is conveyed away from the machine.

As the piston 65 approaches the righthand end of the cylinder 64, the abutment 83 on the rod 80 again engages the switch plunger 85 and the cycle repeated as above described. It should be noted that the operation of the apparatus is completely automatic and work operations are performed upon successive blanks 42' in the chute 94 so long as a supply is maintained in the chute 94. It is to be understood that an actuator 60 operated by oil or hydraulic pressure may be utilized to reciprocate the ferrule carrying arbor or support 50.

Figure is illustrative of a modified form of means for resiliently supporting the arbor or work support 551'. In this form the work supporting arbor 5% is formed with a tenon 115 which is slotted or otherwise configurated to receive and be connected to a member 117 formed of strip steel or other flexible material. The strip 117 is made comparatively thin so as to facilitate limited rotative movement of the arbor 50' during swaging op erations so that the arbor and the work piece carried thereby may return to normal position after each impact of the swaging dies 26.

Figure 11 illustrates another form of support and mounting means for a work carrying arbor 50". In this arrangement the work supporting 50" is formed with a tenon 120. The diameter of the tenon is such as to be snugly received in the end zone of a reinforced flexible rubber tube 121, the tube forming a yieldable or flexible connecting means between the arbor 50" and the piston rod 66 of the actuating means for reciprocating the arbor 56". The tube 121 may be formed of any suitable elastomer so as to provide for limited rotative movement or oscillation of the work and work supporting arbor 50 during swaging operations.

Figure 12 illustrates another form of actuating means of a mechanical character for reciprocating the work supporting arbor and work piece carried thereby. In this form of construction, the frame portion 11 of the ma chine supports a bracket or member 125 which is bored to accommodate a bearing bushing 127. Slidably mounted in the bearing bushing 127 is a rod 129 adapted for reciprocatory movement in the direction of its longitudinal axis.

One end of the shaft or rod 129 is formed with a tenon 130 which is snugly fitted into the end of the spring 54 of the same type shown in Figures 1 and 2. The spring 54 is connected with the work supporting arbor in the same manner as shown in Figures 1 and 2. The spring 54 extends through a bore formed in the bracket 96', the bracket also journally supporting work removing rolls mounted upon shafts 102' driven by a belt 108' from a motor 196.

Also mounted upon the frame portion 11 of the machine is a housing containing suitable speed reducing gearing. Journalled upon the housing and connected with the speed reducing gearing is a shaft 137 which supports a disk 139. The disk 139 is provided with a crank pin 140 which is connected to pin or stub shaft 142 carried by an end zone of the shaft or rod 129 by means of a connecting rod or link 144.

A motor 146 carried by a plate 147 secured to the frame of the machine is provided with a drive pulley 149 which is connected by means of a driving belt 150 with a driven pulley 152 which is of considerably larger diameter than the driving pulley 149. The driven pulley 152 is supported upon a shaft 154 which extends into the housing 135 and drives the speed reducing gearing contained within the housing.

By reason of the difference in diameters of the pulleys 149 and 152 and the speed reducing mechanism contained within the housing 135 the shaft 137 rotates the disk 139 at a'speed satisfactory to carry on the swaging operations. The swaging die arrangement and work feeding chute construction shown in Figures 1 and 2 may be utilized in the same manner with the arrangement shown in Figure 12.

The operation of the arrangement of Figure 12 is as follows: The motor 146, through the driving and driven pulleys 149 and 152, driving belt 150 and the speed reducing mechanism contained within the housing 135 rotates the shaft 137 and disk 139. The rotation of the disk 139 imparts reciprocating motion to the shaft 129 through the connecting rod or link 144 and in this manner the work supporting arbor is reciprocated to perform its functions in a manner similar to the arrangement shown in Figures 1 and 2.

Certain advantages are derived through the use of the driving arrangement shown in Figure 12. As the Work piece and supporting arbor are moved by the crank 144 into the swaging dies 26, the crank pin 140 approaches its limiting position of causing appreciable longitudinal movement of the work and work support in a lefthand direction as viewed in Figure 12. Thus While the crank pin is moved through an angle exemplified by an angle A, which may be upwards of forty degrees, only a very small rectilinear movement of the shaft 129 takes place during this angular movement of the crank pin 140.

This period provides a dwell in the longitudinal move- I ment of the work piece sons to provide ample time for 9. the swaging dies to effect and complete the thread-forming swaging operations.

Upon retraction of the completed work piece by further rotation of the disk 139 and crank pin 140, the latter approaches its maximum limit of movement in causing retractive rectilinear movement of the shaft 129. Thus only minor longitudinal movement of the shaft takes place during the rotation of the crank pin through an angular distance of about forty degrees as indicated at B. During rotation of the crank pin 149 through the angle B, there is very little rectilinear travel of the shaft 129, providing a dwell to facilitate removing the work piece from the supporting arbor by means of the rolls 110. In this phase of the operation, the spring 54 may be slightly stretched longitudinally to compensate for the retarded movement of the arbor when the work piece engages the work removal rolls 110.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

I claim:

1. Apparatus of the character disclosed, in combination, a frame, a member journaled on the frame, means for rotating the member, a pair of dies associated with the member arranged for rotation with the member and reciprocation radially of the axis of rotation of the member, means for causing radial reciprocating movements of said dies during rotation of said member, an arbor formed with a peripheral recess adapted to support a hollow metal workpiece, yieldable means connected with and forming the sole support for the arbor, means for advancing the arbor and workpiece into engagement with the dies whereby the moving dies force the metal of the member into the recess in the arbor and for retracting the arbor and workpiece, said yieldable means providing the sole connecting means between the arbor and the arbor advancing and detracting means, and rotatable means adapted upon retraction of the workpiece from the dies for removing the workpiece from the arbor.

2. Apparatus of the character disclosed in combination, a frame, a member rotatably supported on the frame, means for rotating the member, a pair of dies, means operable during rotation of said member for moving said dies radially of the axis of rotation of the member, an arbor adapted to carry a hollow workpiece, a coil spring connected with the arbor and forming the sole support means for the arbor, guide means for the arbor, automatically operable means for reciprocating the arbor to advance the workpiece into engagement with the moving dies and for retracting the workpiece, said coil spring providing the sole connecting means between the arbor and the means for reciprocating the arbor, and rotatable means adapted to be engaged by the workpiece upon retraction of the workpiece from the dies for removing the workpiece from the arbor.

3. Apparatus of the character disclosed, in combination, a frame, a member journaled on the frame, a pair of dies associated with the member adapted for rotary and reciprocating movements during rotation of the member, means for rotating the member, an arbor formed with a spiral groove adapted to support a hollow workpiece, means for reciprocating the arbor and workpiece carried thereby for moving the workpiece into and out of engagement with said dies, a spring engaging the arbor and forming the sole support for said arbor, said spring being the sole connecting means between the arbor and the reciprocating means therefor arranged for limited rotation about the axis of the rotatable member, and rotatable means engageable with the workpiece during its movement away from the dies for disengaging the workpiece from the arbor.

4. Apparatus of the character disclosed, in combination, a frame, a rotatable member journaled on the assess-e frame formed with a transversely extending chamber, a pair of dies arranged for reciprocatory movement in the chamber, means for rotating the member, means for reciprocating the dies during rotation of the member, an arbor formed with a recess adapted to support a hollow workpiece, resilient means forming a sole support for the arbor, means connected with the resilient means for moving the arbor and workpiece into the path of the reciprocating dies and for retracting the arbor and workpiece, said resilient means forming the sole connecting means between the arbor and the arbor moving means, said reciprocating dies forcing the metal of the workpiece into the recess in the arbor to form an inwardly extending projection on the workpiece, and means en-' gageable with the workpiece for removing the workpiece from the arbor.

5. Apparatus of the character disclosed, in combination, a frame, a rotatable shaft journaled on the frame, a pair of dies disposed in a transversely extending chamber formed in the shaft, means for rotating the shaft, means engageable with the dies during rotation of the shaft for reciprocating the dies in directions radially of the axis of the shaft, an arbor formed with a spiral groove adapted to support a hollow workpiece, means for moving the arbor and workpiece into the path of said dies and retracting the arbor and workpiece, a coil spring engaging the arbor and forming the sole support for the arbor, said spring providing the sole connecting means between the arbor and the arbor moving means, said reciprocating dies forcing the metal of the workpiece into the spiral groove on the arbor to form an internal spiral ridge on the workpiece, and rotatable rolls engageable with the workpiece during its retraction from the dies for removing the workpiece from the arbor.

6. Apparatus of the character disclosed, in combination, a frame, a rotatable shaft journaled on the frame, a pair of dies disposed in a transversely extending chamber formed in the shaft, means for rotating the shaft, a plurality of cylindrical members surrounding the portion of the shaft formed with the transversely extending chamber, means engageable with the cylindrical members during rotation of the shaft for reciprocating the dies, an arbor formed with a spiral groove adapted to support a hollow workpiece, a coil spring connecting with the arbor and forming the sole support for said arbor, drive means connected with the spring for moving the arbor and workpiece into the path of said dies and for retracting the arbor and workpiece therefrom, said coil spring forming the sole connecting means be tween the drive means and the arbor, said reciprocating dies forcing the metal of the workpiece into the spiral groove on the arbor to form an internal spiral ridge on workpiece, and rotatable means engageable with the workpiece during its retraction from the dies for removing the workpiece from the arbor.

7. Apparatus of the character disclosed, in combination, a frame, a rotatable shaft journaled on the frame, a pair of dies disposed in a transversely extending chamber formed in the shaft, means for rotating the shaft, a plurality of cylindrical members surrounding the portion of the shaft formed with the transversely extending chamber, means engageable with the cylindrical members during rotation of the shaft for reciprocating the dies, an arbor formed with a spiral groove adapted to support a hollow workpiece, a coil spring connected with the arbor and forming the sole support for said arbor, fluid actuated means for moving the arbor and workpiece into the path of said dies and for retracting the arbor and workpiece therefrom, said coil spring forming the sole connecting means between the fluid actuated means and the arbor, said reciprocating dies forcing the metal of the workpiece into the spiral groove on the arbor to form an internal spiral ridge on the workpiece, and a pair of rotating rolls engageable with the workpiece during its retraction from the dies for removing the workpiece from the arbor.

. -8. Apparatus of the character disclosed, in combination, a frame, a rotatable shaft .journaled on the frame, a pair of dies disposed in a transversely extending chamber formed in the shaft, means for rotating the shaft, a plurality of cylindrical members surrounding the portion of the shaft formed with the transversely extending chamber, means engageable with the cylindrical members during rotation of the shaft for reciprocating the dies, an arbor formed with a spiral groove adapted to support to hollow workpiece, a coil spring connected with the arbor and forming the sole support for said arbor, means for moving the arbor and work piece into the path of said dies and retracting the arbor and workpiece, said arbor moving means including a rod connected with the coil spring, said coil spring forming the sole connection between the rod of the arbor moving means and the arbor, a member provided with a crankpin, a link connecting the crankpin with the rod, means 12 for rotating thememher, said reciprocating dies forcing the metal of the workpiece into the spiral groove on the arbor to form an internal spiral ridge on the workpiece, and means engageable with the workpiece during its retraction from the dies for removing the workpiece from the arbor.

References Cited in the file of this patent UNITED STATES PATENTS 1,028,526 Baerwalde June 4, 1912 1,676,482 Lapotterie July 10, 1928 1,949,923 Unke Mar. 6, 1934 2,353,008 Bondeson July 4, 1944 2,381,559 Root Aug. 7, 1945 2,441,580 Mageoch May 18, 1948 2,862,215 Gross Dec. 2, 1958 FOREIGN PATENTS 376,230 Italy Nov. 6, 1939 

